FARCIN DU BCEUF. 217 



Upon potato very dry scales of a pale-yellow color 

 rapidly develop. , 



The growth upon blood-serum is less luxuriant, but 

 similar to that upon agar-agar. 



In milk the organism produces no coagulation by its 

 growth, and does not alter the reaction. 



Microscopic study always reveals the organism as the 

 same tangled mass of filaments seen in the tissues. The 

 old cultures are rich in spores, which are very small and 

 develop upon the most superficial portions of the growth. 

 These spores resist the penetration of stains to a rather 

 unusual extent. 



Cultures retain their virulence for a long time : Nocard 

 found one virulent after it had been kept for four months 

 in an incubating oven at 40 C. 



The streptothrix of farcin du bceuf is pathogenic for 

 guinea-pigs, cattle, and sheep ; dogs, rabbits, horses, and 

 asses are immune. 



When the culture or some pus containing the micro- 

 organism is injected subcutaneously into a guinea-pig, a 

 voluminous abscess results. Not long afterward the lym- 

 phatic vessels and glands of the region are the seat of swell- 

 ing and induration, and extensive phlegmons form, which 

 rupture externally and discharge considerable pus. The 

 animal, of course, becomes extremely ill and seems about 

 to die ; instead, it slowly recovers its nonsnal condition. 



In other animals, as the cow and the sheep, the subcu- 

 taneous inoculation results in an abscess relatively less 

 extensive. This ulcerates, then indurates, and seems to 

 disappear, but after the lapse of several weeks or months 

 opens again in the form of a new abscess. 



In animals which are immune or nearly immune, like 

 the horse, the ass, the dog, and the rabbit, the subcuta- 

 neous inoculation is followed by the formation of a small 

 abscess which speedily cicatrizes. 



Intraperitoneal inoculation in the guinea-pig gives rise 

 to an appearance resembling tuberculosis. The omen turn 

 may be extensively involved and full of softened nodes. 



